Background: The prevalence of transgender Veterans (?trans vets?) is on the rise. Transgender individuals experience discord between their self-identified gender and biological sex, defined as gender dysphoria (GD). Untreated and/or undertreated GD is associated with increased mortality and morbidity including depression, anxiety, and suicidality. Hormone therapy is generally the first, and often the only, medical intervention accessed by trans persons with GD who seek to masculinize or feminize their body to be consistent with their gender identity. In 2012, Pharmacy Benefits Management (PBM) issued Criteria for Use (CFU) for trans vet hormone therapy care. In our pilot work, we identified that out of 7,944 trans vets with GD from FY 2005-17, 4,977 were on hormone therapy, with 7-fold variation on one quality of measure recommended by CFU across sites. In order to identify more such gaps in delivery of this care, we need to understand the current patterns of care, determine the degree of concordance with recommendations, and factors driving trans vet hormone care. Objectives: We propose a quantitative study with the following 3 specific aims: 1: Refine methods for identifying trans vets on hormone therapy using VHA data and validate by chart reviews. 2: Examine the hormone therapy care provided to trans vets in VHA. 2a: Describe the current state of hormone care for trans vets in VHA. 2b: Determine the degree that hormone care is concordant with PBM CFU and non-VHA guidelines. 3: Identify patient-, clinician-, and site-level predictors of trans vet guideline-concordant hormone care. Methods: Aim 1: After having identified a population of GD documented trans vets on hormone therapy using national VHA data, we will also consider alternative approaches of identification, including receipt of hormones by opposite sex, and change in coded gender over time, which will be further validated by chart reviews. Aim 2: We will then describe the study cohort in terms of demographics, proportion of those receiving each type of hormone therapy (estrogen vs. testosterone vs. none), route of administration (oral, transdermal, injectable), dosage and titration schedule, and duration of therapy. We will also proceed with the work of identifying key aspects of care recommended by PBM CFU and non-VHA guidelines (e.g. adequacy of laboratory monitoring) against which the current care can be measured. Aim 3: We will apply Generalized Linear Mixed Models to examine factors associated with guideline-concordant hormone therapy care at the patient- (e.g. housing instability), provider- (e.g. availability of trans electronic consultations) and site-level (e.g. trans specialty training offered at site). Anticipated Impacts on Veterans? Healthcare: VHA has an imperative to provide high-quality care to trans vets, which is also a primary goal of our operational partners in the Lesbian, Gay, Bisexual, and Transgender (LGBT) Health Program in the Office of Patient Care Services. This study will be the first to provide an assessment of the quality of hormone therapy care received by trans vets served by VHA, as well as to refine methods to identify trans persons on hormones in VHA data. In addition, this proposal will lay the groundwork for a follow-up qualitative study to identify best practices associated with the delivery of guideline-concordant hormone therapy care in trans vets. This work is firmly in line with the call to provide high-quality care irrespective of gender and sexual orientation, as outlined in the VHA Strategic Plan, and Blueprint for Excellence, and addresses the 2017 HSR&D priority area of healthcare equity and health disparities.